1. Field of Invention
The present invention relates to an electrical circuit identification means, especially to electrical circuit identification means by which the position of a socket at a remote end that is corresponding to each main power switch and connected to the same circuit in a power control panel can be found out under the condition that the circuit is conducted.
2. Description of Related Arts
Refer to U.S. Pat. No. 3,924,179 “Method for certifying dead cables or conductors by determining current pulse polarity”, a DC pulse transmitter 20 is connected through test lead 21 “A” to conductor 23 under test while clamp-on jaws 51 of DC pulse receiver 50 are clamped around the conductor 23 under test to receive signals from the DC pulse transmitter 20 for certifying a dead conductor or cable.
In the above method and apparatus, a dead insulated electrical conductor among a plurality of conductors is certified by determining the polarity of a net DC pulse in the conductor. Only a dead conductor or cable can be detected. As to conductive circuit, the prior art is unable to determine relationship between main power switches and power sockets.
Refer to U.S. Pat. No. 5497094 “Electrical circuit identification means”, a transmitter is plugged into the receptacle of the line to be traced. Getting power from this line, the transmitter imparts to this line, a spike by virtue of the sudden application of an uncharged capacitor of the transmitter as a momentary “short-circuit” load to this line. The pulse thus produced is detectable by a receiver. By a blinking indicator light or a sounding buzzer, a line or lines carrying the load current is located.
The receiver uses a pickup coil to receive the pulse. However, if there are some other lines, mobile phones, computers or other electronics in use near the line/line under test, the electrical signals generated cause interference problem. Thus the receiver has errors in identifying the signals received and the detection accuracy is reduced.
Refer to U.S. Pat. No. 6,163,144 “Electrical circuit tracing apparatus using modulated tracing signal”, an electrical circuit tracing apparatus includes a transmitter being connected to the circuit to be identified such as a power socket and a receiver placed in proximity to the circuit such as power control panel to find out the elements of the circuit such as main power switches. The transmitter has an electrical current signal generator including a low frequency oscillator and a high frequency gated oscillator modulated by the low frequency oscillator and a current modulator. Thus a high frequency current signal is induced in the circuit that is modulated at the low frequency. The receiver has a circuit including an inductive pick-up that is tuned to the high frequency so as to induce in the puck-up a current of the high frequency when the coil is excited by the magnetic field of the circuit. The receiver further has a signal strength indicator such as a line of LED lights is used to signal users and the signal strength varies in accordance with the magnitude of the current in the pick-up.
By low frequency signals as carrier, high frequency signals are transmitted and received by the transmitter and the receiver mentioned above. Thus the manufacturing cost is high.
Thus there is room for improvement and there is a need to provide an electrical circuit identification means that overcomes the above shortcomings and has high accuracy.